A conference call refers to a communication among more than two endpoints. Each endpoint sends an audio stream to a conference bridge. The conference bridge mixes the audio streams and transmits the mixed streams back to the endpoints. According to a known conferencing technique, the conference bridge establishes bidirectional unicast connections to each endpoint. Establishing bidirectional unicast connections to each endpoint, however, may not provide for efficient use of bandwidth.
According to another known conferencing technique, a multicast backbone (MBONE) multicasts audio streams from each endpoint to the other endpoints. The multicast backbone, however, requires the endpoints to support multicast processing. For example, the endpoints may be required to subtract their own speech or to perform audio mixing. Accordingly, legacy endpoints may not be able to participate. Moreover, this technique may require a large amount of digital signal processing. According to yet another known conferencing technique, conference calls may be distributed using routers such as media switches. The conference calls, however, are limited in the number of participants due to a centralized audio mixing architecture. Therefore, providing for efficient, flexible, and effective conferencing may be difficult in certain situations.